Porous substrates are available for various filtration and separation processes. For example, porous substrates with catalytic materials deposited on the substrate are commonly used to reduce particulate emissions and convert toxic exhaust gas into less toxic gases. Substrates that have relatively high porosity (i.e., percentage of void space in the material) and relatively high thermal shock resistance (e.g., due to low thermal expansion) may provide the greatest efficiency and effectiveness. While a variety of materials have been used in particulate filter and catalytic converter applications, cordierite has proven to be well suited to such use.
Cordierite is commonly formed from raw materials including magnesia, alumina and silica in powder form. Extrusion of ceramic powder materials has proven to be an effective and cost efficient method of producing ceramic substrates for the environmental controls industry. However, there is an upper limit to the porosity in extruded ceramic powder materials. If the porosity of the extruded substrate formed from powder ceramic materials is exceeded, the strength and functionality of the substrate may be compromised.
Therefore, there exists a need for a cordierite substrate having high porosity and permeability, while the strength is maintained for various applications.